When forming with fasteners having a head and threaded shank with a tool-receiving recess in the head of the shank for receiving a screw driver or other driving tool, it is important that the recess-defining walls meets standards so that the driving tool properly fits into the recess and provides a maximum driving or turning torque for turning the threaded fastener. Typically, deviations with respect to the standard configuration of the driving recess are caused by wear or breakage of a portion of the punch. This allows metal to bulge at an area in one of the recess walls where the punch is worn or broken off. That is, during the formation of the recess, a tool is pushed into the metal; and the metal conforms to the shape of the punch including the worn away or broken away cavity areas, forming a bulge of extra metal at the worn away or broken cavity areas which prevents the mating of the driving tool directly and exactly in the fastener recess.
A problem with the detection of such minor bulges occurring almost anywhere within the recess is that the current manner of checking the fastener recess is to merely check the depth. Unless the bulges at the bottom wall of the recess interfere with the full insertion of the depth checking instrument, the bulge will not be detected using current standard measuring devices. Also, sometimes the punch tip may break so that a bulge may appear on the bottom of the wall of the recess; while the maximum depth be engaged is still apparently the full depth and most, or a substantial portion of the recess. Thus, there is a need to detect the punch wear or breakage of the punch during the manufacturing process, and also to detect, by examining the fastener, when the fastener is no longer meeting the standards for its driving recess. There is a need to eliminate and to detect any sloppy fit between the driving tool and the recess-defining walls and to also determine the condition of the punch used in the manufacturing process.